The detection and diagnosis of anatomical features of interest such as pulmonary nodules is a standard procedure in radiological practice. The speed and sophistication of current computer-related systems support development of faster and more sophisticated medical imaging systems. The consequential increase in amounts of data generated for processing, and post-processing, has led to the creation of numerous application programs to automatically analyze the medical image date. Thus, various data processing software and systems have been developed in order to assist physicians, clinicians and radiologists, etc., in evaluating medical images to identify and/or diagnose and evaluate medical images. For example, computer aided detection (CAD) systems have been developed to automatically identify “suspicious” regions such as lesions or pulmonary nodules, which could be an indication for lung cancer or may be metastases from other types of cancer.
CAD systems are known which automatically detect (identify and delineate) morphologically interesting regions (e.g. lesions, nodules, calcification) and other structurally detectable regions that might be of clinical relevance. The CAD software automatically marks or highlights medical anomalies in medical images provided from e.g. computer tomography, magnetic resonance, ultrasound or x-ray scanner. For example, in the analysis of a lung image seeking possibly cancerous nodules, the CAD system will mark the nodules detected.
However, false positive markings often occur close to the beating heart due to image artefacts caused by cardiac motion. The heart beat causes erroneous displacements of the image slices, which in turn leads to an apparent discontinuity in, for example, vessel structures, airways and other anatomical features, which can be misinterpreted by the CAD software and thus lead to false positive markings during the computer aided detection process.
False positive markings may also occur due to artefacts caused by breathing motion, photon or energy starvation areas or streak artefacts caused by high-density objects such as metal prostheses, surgical clips, or dental fillings. This can make it more difficult for a radiologist, physician or clinician to classify and interpret the detected features of interest. This could result in an increased period of time needed to assess the CAD results and lead to assessment errors by the physician due to degraded concentration.